INTEGREATED SYSTEM OF METALWORK PRODUCTION.pdf

7/25/2019 INTEGREATED SYSTEM OF METALWORK PRODUCTION.pdf

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Table of Contents

Index of Figures ..................................................................................................................................... 26

1. Objective of Project ......................................................................................................................... 3

2. Spectrum of Work Parts .................................................................................................................. 3

2.1. Item I - stepped shaft .............................................................................................................. 3

2.2. Item IIcasing .......................................................................................................................... 4

2.3. Item IIIsleeve 1 ..................................................................................................................... 5

2.4. Item IVsleeve 2 .................................................................................................................... 6

2.5. Item Vplate 1 ....................................................................................................................... 7

2.6. Item VIsleeve3 ..................................................................................................................... 8

2.7. Item VIIlever....................................................................................................................... 9

3. Resources ...................................................................................................................................... 10

3.1. Available machines ................................................................................................................ 10

3.2. Human resources................................................................................................................... 14

4. Flow Modelling .............................................................................................................................. 15

4.1. Flow process chart ................................................................................................................. 15

4.2. Aggregated material flow by machines ................................................................................. 15

5. Spatial Structure. ....................................................................................................................... 16

6. Method of Scheduling ................................................................................................................... 17

7. Production Schedule ..................................................................................................................... 17

8. Resource Utilization ...................................................................................................................... 19

9. Reports .......................................................................................................................................... 22

10. Conclusions ................................................................................................................................ 23

10.1. Critical path ....................................................................................................................... 24

10.2. Bottlenecks ........................................................................................................................ 25

11. Bibliography ............................................................................................................................... 26


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INTEGREATED SYSTEM OF METALWORK PRODUCTION PAGE3

1. Objective of Project

The objective of this project is planning of production of various items usingmachines available in an

assumed production hall. The first part of the project includes the choice of items to be made,

assigning necessary types and times of tooling for each part, choosing machines and ways oftransport, and planning of locating them in the production hall. Next step is using computer aided

machining software. It will allow us to optimize the production process itself, but it will also improve

the use of machines and reduce time of work and demurrage, which makes the production

adjustable to dynamically changing market needs

2. Spectrum of Work Parts

Selected objects are made of semi-finished steel products and they require fallowing machining

processes: turning, milling, drilling, grinding, tempering. Each item in the final stage is checked for

preserving the required dimensions and tolerances on shape and position-coordinate measuring

machine. The following items were presented with the scheduling of machining sequence.

2.1. Item I - stepped shaft

Figure 1 Stepped shaft

Semi-finished product

shaft 45x300, with prepared Centring holes and face surfaces

Machining planning

No. Operation of technological process Machine Identification

1.Profile turning-threading M30, groove

machiningTurning Centre TC

2. Milling key way and slot Milling Centre MC

3. Finish grinding Grinder G

4. Quality assurance(control of shapes anddimensions)

Coordinate Measuring Machine CMM


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2.2. Item II casing

Figure 2 Casing


Steel cuboid 200x150x90

Base: central hole 46,25H6

Machining planning


1. Processingdatumhole 46,25H6 Milling Centre MC

2. Milling surfaces Milling Centre MC

3. Machining 14, 6 and threading M14, M6 Milling Centre MC

4. Quality assuranceCoordinate Measuring

MachineCMM


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2.3. Item III sleeve 1

Figure 3 Sleeve I


Rolled rod 120

Base: rolledsurface 120

Machining planning


1. Turning cylindrical surfaces 63j6, 55 Turning Centre TC

2. Turning phases Turning Centre TC

3.Performance of hole 35H6 and stepped

holes 13, 24Milling Centre MC

4. Performance of side hole 15 Milling Centre MC

5. Grinding surface 63j6 Grinder G

6. Grinding hole Grinder G


Machine

CMM


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2.4. Item IV sleeve 2

Figure 4 Sleeve II


Rolled rod 66

Base: rolled surface 46

Machining planning


1. Face milling Turning Centre TC

2. Rough turning Turning Centre TC

3. Profile turning Turning Centre TC

4. Finish turning Turning Centre TC

5. Key way Milling Milling Centre MC

6. Drilling Milling Centre MC

7. Finishgrinding Grinder G

8. Hardening Induction Hardening Machine IH


MachineCMM


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2.5. Item V plate 1

Figure 5 Plate

Semi finished product

Rolled rod 212


Machining planning


1. Turning the cylindrical surface 140 Turning Centre TC

2. Turning phases and rounding Turning Centre TC

3.Performance of holes 145, 131, 120,

95H8, 85, 73, 8, 6, 3Milling Centre MC

4. Tapping of holes 8 Milling Centre MC


MachineCMM


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2.6. Item VI sleeve3

Figure 6 Sleeve with flange

Semi finished product

Rolled rod 120


Machining planning


1. Turning cylindrical surfaces 60j6 Turning Centre TC

2. Turning phases Turning Centre TC

3. Performance of hole 35H6 and holes 13 Milling Centre MC

5. Grinding surface 60j6 Grinder G

6. Grinding hole 35H6 Grinder G

7. Tapping M36 thread Grinder G


MachineCMM


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2.7. Item VII lever

Figure 7 Lever


Forging

Base: hole 20H7

Machining planning


1.Preparation of the baseperformance of

20H7 holesMilling Centre MC

2. Face milling Milling Centre MC


MachineCMM


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3. Resources

3.1. Available machines

a) Turning Centre

Figure 8 Turning Centre

Horizontal turning centre

For turning of shafts: using tusk, the turned item is fixed in the spindle grip

Provided with a tools warehouse

Presence of a worker responsible for tooling and changing of items is required


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b) Milling Centre

Figure 9 Milling centre

Vertical milling centre

Milling the external surfaces and holes

Drilling and threading the holes

Provided with a tools warehouse

Presence of a worker responsible for tooling and changing of items is required


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c) CNC grinder

Figure 10 CNC Grinder

For grinding the external surfaces and holes

For grinding small and medium elements for unit and series production

d) Coordinate Measuring Machine

Figure 11 Coordinate Measuring Machine

High quality measuring

Measurement of complicated items

Multisensor machine for different measuring jobs


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e) Induction Hardening Machine

Figure 12 Induction Hardening Machine

Heat treatment; induction hardening

For induction hardening the surfaces of shafts, bolts, sleeves, flat surfaces, sleeve fronts, gear

wheels

High efficiency, series treatment

f) Forklift

Figure 13 Forklift

Manual forklift with a scale

Capacity of 2500kg


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3.2. Human resources

According to Figure 16 "Diagram of a 2-cellular production hall", there will be two cells equipped with

machines. In first - two milling and turning centres. In second - induction hardening machine, grinder

and coordinate measuring machine. All of machines have to be operated on some level.

a) Cell one

Two milling and turning centres will be operated by 4 persons from. There is need to manual

change of objects.

b) Cell two

Grinder will be operated by one qualificated employee

CMM will be operated by one qualificated employee

c) Both cells

There is need of two persons that would transport semi-finished products between

machines.


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4. Flow Modelling

4.1. Flow process chart

Routes present planned machining sequence of products.

Figure 14 Flow process chart. P1-P7 products; TC turning center; MCmilling center; G grinder; IH induction

hardening machine; CMMcoordinate measuring machine; S1,S2 storages.

4.2. Aggregated material flow by machines

Routes present material flow that helps to find disproportion in use of machines.

Figure 15 Network of material connections


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Both figures help to findpossible bottle-necks. It is easy tonotice that MC and CMM have to work on

more parts then other machines.

5. Spatial Structure.

Main aim of setting spatial structure is to shorter ways of semi-finished products, this leads to short

times of transport and work that is put into it. Less work = less money spent.

At first step machines were supposed to be set by criterion of product specialization as it is shown in

table 1.

Cell Machine P1 P3 P4 P6 P2 P5 P7

1

IH 4

G 3 3 3 3

TC 1 1 1 1 1

2MC 2 2 2 2 1 2 1

CMM 4 4 5 4 2 3 2

Table 1 Spatial structure set by criterion of product specialization

But after analyzing this structure in front of flow process it was noticed that products would flow

back to previous cell which is waste of time. Observation was cause of working out better solution

and after taking into account this fact final structure was set by criterion of organisational

concentration [Table 2].

Cell Machine P1 P2 P3 P4 P5 P6 P7

1TC 1 1 1 1 1

MC 2 1 2 2 2 2 1

2

G 3 3 3 3

IH 4

CMM 4 2 4 5 3 4 2

Table 2Spatial structure set by criterion of organisational concentration

Figure 15 visualizes final spatial structure.


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Figure 16 Diagram of a 2-cellular production hall

6. Method of Scheduling

In the educational version of Preactor 9.3 there are three methods of scheduling: forward

scheduling, backward scheduling and APS (Advanced Planning System). Present project uses forward

scheduling, providing a solution characterized by the earliest date of completion of production. In

addition operations were set in compliance with FIFO (First In First Out)strategy. The earliest ordersare executed first and the latest are at the end of the list.

7. Production Schedule

Gant chart below presents the scheduling of process.


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Figure 17 Gantt chart


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8. Resource Utilization

Figure 18 Resource utilization chart. Red line indicates average machine utilization(15,39%)

Charts below present theindividual use of machinesin %.

10,56%

1,67%

87,77%

Turning centre TC1

Util ization time Set-up time No work time

8,75%

1,25%

90,00%

Turning centre TC2

Utilization time Set-up time No work time


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16,11% 2,64%

81,25%

Milling centre MC1

Util ization time Set-up time No work time

15,90% 2,22%

81,88%

Milling centre MC2


10,67%1,94%

87,39%

CNC grinder - G


30,35%

4,17%

65,48%

Coordinate Measuring

Machine CMM


2,08% 0%

97,92%

Forklift 1


8,33%0%

91,67%

Forklift 2



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In analysis of the chart presented above, one concludes that uniform loadings are not possible. The

forklifts are the least used machines in this chart, because they carry entire series of products, not

individual parts.

The most used machine is Coordinate Measuring Machine. Every part must be checked, so the

company can provide high quality of products. This problem could be resolved by reducing steps of

quality assurance to most important parts or not checking all objects but only a part of them. In

order to provide high quality of products, the system has to assume a high chance of dimensional

incapability, therefore a big part of the production must be checked, so the usage of CMM remains

very big. Automation of quality assurance could also solve the problem.

4,17% 0%

95,83%

Induction Hardening Machine

IH



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9. Reports

Table 3 Schedule performance metrics

Table 4Summary of orders


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10.Conclusions

Job Completion Data

Total Minimum Average Maximum

Lead time 2d 4h 20min 3h 39min 7h 29min 11h 23min

Added Value Percentage 23,43 49,03 87,36

Resource Data

Minimum Average Maximum

Working Percentage 4,3 24,51 62,61

Setup Percentage 0 3,18 8,6

Schedule Duration 11h 38 min

Table 5 Shorten schedule performance metrics

Conclusions are based on reports collected from Preactor APS program, presented in the previous

section.

Our criterion was integration of production system. Optimal solution has been found using Preactor.

Characteristic parameters of the system are presented below.

Length of the ProductionCycle(LPC)

In the present system, the production of the FIFO scheduling forward - by benchmarks - the

length of the production cycle is 11 hours 38 minutes.

This is the time it takes to complete a set of tasks, so this value should decrease to the

minimum, which proves most effective use of work time for each machines. The lower the

LPC time, the faster the company can accept new orders and generate more profits.

Degree of Utilization of Resources (DUR)

Resources are machines and forklifts. Value DUR should strive for the maximum, however

forklifts significantly decrease the average utilization of resources. At the same time at this

point it is worth mentioning that loadings should be similar if we want to avoid bottle necks.

If one machine is overloaded other machines have to wait until previous steps are executed.

Order Flow Time (OFT)

The value of the order flow time strive for minimum because it presents the time, an object

stays in the system. In this project the total execution time is 2d 4h 20min which is collective

timeforall orders. This is not atimeof technological processes, because in addition tothe time


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requiredto performeach operation,downtimeis also taken into account. The pointis to

obtainthe smoothest possibleflow.

The percentage ofadded value

The percentage of added value is also a measure of the effectiveness of the system. The

highest values are recommended, because it grows during an ongoing machining of the work

piece. This is the equivalentto sayingthat during downtime, that is, when the object is waiting

for its turn, the added valuedoes not change. In the present case it is much about 49.03%.

10.1. Critical path

Longest sequence ofactivities in aproject plan which must becompleted on time for theproject to

complete ondue date.An activity on the critical path cannot be started until its predecessor activity

is complete; if it is delayed for aday,the entire project will be delayed for a day unless the activity

following the delayed activity is completed a day earlier. Figure 19 shows critical path on Gant chart.

Figure 19 Critical path

As could be seen critical path is mainly processing of item P1. Whole time is 11h and 38min if any

operation of critical path will be longer, final time will get longer too.
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10.2. Bottlenecks and possible improvements

Bottlenecks are caused by overlapping of orders at the same time - conflict situations arise, e.g.

Different types of treatment areperformed at the same machines. This leads to delays and waiting

for the next objects to bemachined. This is undesirable, however, with a limited number of

resources, and a more complex structure of the socket it is hard to avoid this phenomena. One

solution could be to equip a production hall with an additional machine, but only if such a step would

be profitable for the company.

Figure 20 Bottlenecks on Gantt chart

On the figure above we can see bottlenecks of order P6/CARGOTECH/02. We can easily notice that

the largest exist before CMM and as it was said in chapter "Resource utilization" times of operations

should be shortened or new machine should be bought. There is also need of intermediate store

because CMM is a bottleneck for almost every part.

Another way to increase the efficiency of the production process is to include an industrial robot to

automate the material handling. This solution requires scheduling of the robot, and makes the

planning of process more complex, but it would increase the productivity significantly.

10.3. Summary

The integration of the production system manifests itself in sockets cooperation, as well as in the

stream intert wining activities around basic operations, such as transport and storage activities or

setup. The integration therefore allows a flexible response to market needs, changes and

modernization ofproduction processes. One should therefore seek to obtain it, which will increase

the productivity and efficiency of the entire system.


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Index of Figures

Figure 1 Stepped shaft............................................................................................................................. 3

Figure 2 Casing ........................................................................................................................................ 4

Figure 3 Sleeve I ....................................................................................................................................... 5

Figure 4 Sleeve II ...................................................................................................................................... 6

Figure 5 Plate ........................................................................................................................................... 7

Figure 6 Sleeve with flange ..................................................................................................................... 8

Figure 7 Lever .......................................................................................................................................... 9

Figure 8 Turning Centre ......................................................................................................................... 10

Figure 9 Milling centre ........................................................................................................................... 11

Figure 10 CNC Grinder ........................................................................................................................... 12

Figure 11 Coordinate Measuring Machine ............................................................................................ 12

Figure 12 Induction Hardening Machine ............................................................................................... 13

Figure 13 Forklift ................................................................................................................................... 13

Figure 14 Flow process chart .....................................................................Error! Bookmark not defined.

Figure 15 Network of material connections .......................................................................................... 15

Figure 16 Diagram of a 2-cellular production hall ................................................................................. 17

Figure 17 Gantt chart ............................................................................................................................ 18

Figure 18 Resource utilization chart ...................................................................................................... 19

Figure 19 Critical path ........................................................................................................................... 24

Figure 20 Bottlenecks on Gantt chart ................................................................................................... 25

11.Bibliography

[1] M. Siemitkowski, INTEGRTED SYSTEMS OF PRODUCTION - lectures, Gdask: GUT, 2014.

[2] Preactor International Ltd., Preactor - Podrcznik uytkownika, Warszawa: Prtczyski, 2004.

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INTEGREATED SYSTEM OF METALWORK PRODUCTION.pdf